I would love the ability to add (at least, I have a 12.2 tablet so more would be preferable) three boxes with customizable choices like a red underline, blue box .4 blue pen. This way, I could flip from items I use all the time much quicker by just using tapping the box I customized to my favorite I presets.

the software is amazing. But i often change color and brush types when i am making a note. It is a bit inconvinient that i should click on the dropdown menu then select what i want. That means 2+ extra clicks before i can do actual editing. In most of the cases I switch between 2 or 3 colors or brush types, can you make a sticky shortcut menu which contains the recently used ones? That will make color changing and tool changing more quickly and make the editing more efficiently.

Since I am regularly using certain tool combinations like "pen; 0,5 mm; black", and "pen; 0,8 mm; violet" and many others, I would appreciate some kind of "one touch customizable tool kit" where I can save my regularly used settings for tools, and access them with only one touch.
It is like the pencil case you used in school, except you can freely create your own tools the way and in the combination you need them.
Other (for me less likeable but still) way to implement this kind of feature: an automatic list of recently or mostly used tools / tool combinations.

This would make working on notes much faster and easier (and sometimes less bothersome, even though Papyrus is a great app), and also more creative in a certain way.